It is known that curing EPDM rubber with phenolic curative gives good mechanical properties but, as predicted by Hoffman, infra, the curing of EPDM rubber with phenolic curative has not been accepted commercially.
Thermoplastic elastomeric (elastoplastic) compositions consisting of blends of polyolefin resin and cured EPDM rubber exhibiting superior physical properties including improved tensile strength, are known. Belgium Pat. No. 844,318 issued Jan. 20, 1977, and U.S. Pat. No. 4,130,535 issued Dec. 19, 1978. The aforesaid improved compositions are economically attractive because they may be extended with extender oil and carbon black which additives improve properties including processability and oil resistance while lowering the cost. However, compositions exhibiting better oil resistance are needed to meet high performance specifications where exposure to organic solvents or oil at high temperature is encountered. Surprisingly, blends of polyolefin resin and EPDM rubber cured with phenolic curative exhibit superior properties including superior oil resistance as compared with blend compositions which are identical except for the EPDM rubber being cured with other curatives.